<?
session_start();

define('_GO'    , "GO");

if(!$_SESSION["modelStorage"]){
  
  $_SESSION["modelStorage"] = array();
}else{
  
  /* Do nothing */
}

/**
* search the model entry in modelStorage 
* YES: do nothing
* NO : echo GO
*
*/
$key = array_search($_POST["modelEnt"], $_SESSION["modelStorage"]);

if(strlen($key) > 0){
  
  echo  "";
}else{
  
  $lastIndex = sizeof($_SESSION["modelStorage"]);
  
  $_SESSION["modelStorage"][$lastIndex] = $_POST["modelEnt"];

  echo  _GO;
}

session_commit();

?>